Remove parenthesis and its content from the Artist field

[LyricsLover]

The first search result for "remove content in brackets" already shows:

Remove Parentesis & Square Brackets Content

You could try an action of the type "Replace with Regular Expression" Search string: \s*\(.* Replace with: (leave empty) Works for text where the round brackets are the first brackets, just like your example

Adjusted for Convert Tag -> Tag instead of an Action it would be
$regexp(%ARTIST%,'\s*\(.*',)
for the most easy variants of
Another Artist (with text to remove)

As long as the OP does not provide the actual real content of the ARTIST fields, we can only guess what would match it. The same applies to some of the more advanced examples mentioned above.